An advanced mobile communication system (beyond the third generation (B3G) or the fourth generation (4G)) as a new system different from the third generation (3G) mobile communication system provides various multimedia services with high transmission rate.
Mobile communication environment of the advanced mobile communication system has a configuration of a nested wireless network, i.e., a network configuration of multiple cell environment, where multiple picocells within one microcell are gathered and form a hotspot region to have a nested service region.
In such an advanced mobile communication system working in the multiple cell environment, a multimedia communication with an ultrahigh speed is required even while a mobile terminal is moving at high speed, same as while the mobile terminal stops. Further, a broadband (20 MHz bandwidth in the advanced mobile communication system) is required in order to accommodate the multimedia services of ultrahigh speed, and a cell radius (radius of picocell is estimated to be around 30 m, radius of megacell is estimated to be around 10 m) needs to become much smaller in order to efficiently use the frequency.
Due to a smaller cell radius and a faster mobility of the mobile terminal, handover frequently occurs and load of a network increases, thereby requiring even faster handover processing.
In other words, the handover occurs once every few minutes in the conventional 3G mobile communication system, but, in the advanced mobile communication system, the occurrence number of the handover increases and intervals of the occurrence time decreases, so that the handover occurs once every few seconds or every several tens of seconds.
In the advanced mobile communication system where such frequent handover has to be processed, unnecessary handover may occur, causing overhead in signaling. This results in degradation in performance of the system.
Further, when such frequent handover is not rapidly processed, the performance of the system also declines, and thus a study on the handover processing considering a faster mobility of the mobile terminal is required.